public class test03 {
    /**
     * Definition for a binary tree node.
     * public class TreeNode {
     *     int val;
     *     TreeNode left;
     *     TreeNode right;
     *     TreeNode() {}
     *     TreeNode(int val) { this.val = val; }
     *     TreeNode(int val, TreeNode left, TreeNode right) {
     *         this.val = val;
     *         this.left = left;
     *         this.right = right;
     *     }
     * }
     */
        public TreeNode insertIntoBST(TreeNode root, int val) {
            if(root==null){
                return new TreeNode(val);
            }
            if(root.val<val){
                root.right = insertIntoBST(root.right,val);
            }else{
                root.left = insertIntoBST(root.left,val);
            }
            return root;
        }
}
